Push-type information transmission has recently been widely used where advertisements and the like are transmitted from server devices of business operators to mobile terminals owned by users. As means for push-type information transmission, SMS (Short Message Service) and push mail are commonly used. Advertisement transmission methods using push-type information transmission have a problem in which access concentration to a server occurs in response to messages that have been simultaneously distributed to a large number of mobile terminals, triggering a transitional congestion state in the network.
As means to avoid traffic concentration caused by such push-type information transmission, a method of lightening network loads by controlling data transmission bands can be considered. For example, PTL 1 describes a technique that, in a data transmission service, optimizes a network by consecutively accumulating network performance information of respective data transmission and reflecting the analysis result thereof to the next transmission policy.